#include <stdio.h>
int main()
{
	int k = 0;
	int n = 1;
	double Sn = 1;
	
	scanf("%d", &k);
	while ( Sn <= k )
	{
		n++;
		Sn += (1.0 / n);
	}
	printf("%d", n);
	return 0;
}
